1. Field of the Invention
This invention relates to a motion picture camera having an auto-focus adjusting device for automatically focusing a shooting lens on an object and yet for permitting the auto-focusing to follow variations in the distance between the shooting lens and object.
2. Description of Prior Art
There have been various proposals with respect to the auto-focusing of the shooting lens in cameras. It has been desired to automate the focus adjustment of the camera as this is the only manual adjustment which has been left in the camera. Particularly, in motion picture cameras such as 8 mm cine-cameras, video cameras, TV cameras or the like, most of which have a zoom lens, it has been customary to take a complicated procedure in which a shooting lens is focus-adjusted after the focal length thereof has been set at maximum, that is, at the furthest viewpoint, and then to reset at such a focal length as required by an operator for shooting. For such a reason among others, it is very significant to realize an auto-focus adjustment of a shooting lens particularly in the motion picture cameras.
Upon realizing the auto-focus adjustment in the motion picture cameras, there is a problem as to the manner in which it is practically used in what manner. That is, among another, it must be determined that the shooting lens is only once auto-focus adjusted at the initial stage of a shooting or that the shooting lens is continuously auto-focus adjusted through the shooting. This problem is important in the actual shooting. If the problem is successfully settled, the shooting can be carried out very effectively.